March 8, 2011 (Orlando, Fla. ) -- Women aged 70 and over should continue to get regular Pap smears to screen for cervical cancer, a study suggests.

The study was presented at the Society of Gynecologic Oncology's Annual Meeting on Women's Cancer.

Researchers found that women aged 70 and over account for more than one in 10 cases of cervical cancer in the U.S. -- and that they're more frequently diagnosed with advanced cancer that is harder to treat than cervical cancer diagnosed in younger women.

The American Cancer Society and the American Congress of Obstetricians and Gynecologists recommend discontinuation of cervical cancer screening between 65 and 70 years of age in women with adequate previous screening and no abnormal test results in the preceding 10 years who are not otherwise at high risk.

"But the rationale behind those guidelines is unclear," says study head Malgorzata Skaznik-Wikiel, MD, of Magee-Womens Hospital of the University of Pittsburgh Medical Center.

"We think those screening guidelines may lead to an increased incidence of cervical cancer in women aged 70 and over. Based on our data, we suggest screening of this age group, taking into account factors such as life expectancy and [other medical conditions]," she tells WebMD.

Skaznik-Wikiel suggests that older women follow the same screening schedule as younger women -- yearly Pap smears or Pap smears every three years after three consecutive negative tests.

Comparing Cervical Cancer Rates

Skaznik-Wikiel and colleagues obtained data from the National Cancer Institutes' Surveillance, Epidemiology, and End Results (SEER) database Program for the years 2000 through 2006.

A total of 18,003 women were diagnosed with cervical cancer during that period; 12% of them were aged 70 and older.

That corresponds to eight cases per 100,000 women aged 70 and over per year, Skaznik-Wikiel says.

"With women living longer, the [rate] is going to increase," she says. The average life expectancy of white and African-American women is now 81 and 77 years, respectively, up from 76 and 68 years four decades ago, according to Skaznik-Wikiel.

Women aged 40 to 44 had the highest rate of cervical cancer, accounting for 15% of all cases.

The study also showed that only 41% of women above age 70 were diagnosed with tumors that could be surgically removed vs. 79% of women under 30.

Also, women aged 70 and over were most frequently diagnosed with advanced (stage IIIB) cervical cancer, while women under 30 were most commonly diagnosed with early-stage (IA1) disease.

Twenty percent of women 70 and over were diagnosed with advanced stage IIIB disease, while 31% of women under 30 had early-stage (IA1) disease.

False-Positive Pap Smears

Asked to comment on the study, Kathleen Schmeler, MD, of University of Texas M.D. Anderson Cancer Center in Houston, says that a strength of the study is its large size.

"But the study is limited by the lack of information on whether women had regular Pap smears throughout their lives," she tells WebMD.

"We know from previous studies that approximately 50% of women who develop invasive cervical never have never had a Pap smear and another 20% didn't have one in the three to five years prior to diagnosis.

"The high rate of cervical cancer at advanced stages in women aged 70 and over could therefore be due to a lack of lifetime screening," Schmeler says.

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.